Selvedge-forming device with independent control and eccentric drive system

ABSTRACT

A selvage-forming device (1) for a loom includes yarn guide structures (2, 3, 5) to guide at least two selvage yarns (8, 11) that are alternating raised and lowered to form a selvage shed (12). These yarn guide structures are powered through the intermediary of eccentrics driven by their own independently controlled drive (13) and an eccentric drive coupling-bracket (16) that creates a motion by which one selvage yarn (8) is additionally shifted transversely to form mutually crossing interlacings.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a selvage-forming device for a power loom, withyarn guide structures to raise and lower at least two selvage yarns.

2. Related Art

Selvage-forming devices cooperating with selvage yarns are used in loomsto form a fabric selvage or a waste band. The selvage yarns are guidedin yarn guide structures which raise and lower these yarns to subtendsheds in which the fillings are laced into the selvage yarns in apredetermined pattern. The yarn guide structures usually are fitted withyarn guide elements in the form of circular, oval or slotted apertures.The selvage yarns also are called catch threads.

Selvage-forming devices for at least two selvage yarns are known.Therein a first selvage yarn is moved up and down in one plane while asecond selvage yarn is moved up and down in the opposite direction tothe first one and simultaneously is displaced transversely to the planeof the up-and-down motion, whereby the two selvage yarns cross eachother.

The known selvage-yarn devices contain a needle moving in a plane andcomprising an eye guiding a first selvage yarn. Moreover they containtwo yarn guide structures fitted with crossed slots to guide a secondselvage yarn and which are displaced oppositely to the needle. In theprocess the yarn guide structures with the crossed slots also moverelative to each other, and, because of the relative displacement of theslots, the second selvage yarn is shifted perpendicularly to theabove-mentioned plane, and as a result the two selvage yarns will cross.

Such a selvage-forming device is described in U.S. Pat. No. 4,478,256.The selvage-forming device is driven jointly with the loom's harnesses.Accordingly this selvage-forming device only allows interlacings, i.e.weaves, which are determined by the paths of the harnesses. Anotherselvage-forming device is disclosed in U.S. Pat. No. 3,171,443 and isdriven by the same drive elements of the loom drive system. The drive isfairly complex. A change in interlacing is possible only aftersubstantial labor.

The object of the invention is to create a selvage-forming device of thetype discussed above that allows changing in a simple manner the weaveof selvage yarns and fillings. cl Summary of the Invention

This problem is solved by providing an independently controlled drive toraise and lower the selvage yarns in a mutually opposite manner by meansof eccentric drives that are connected to the linearly guided yarn guidestructure. The yarn guide structures of at least one selvage yarnimplement the crossing of this selvage yarn while it is being raised andlowered with another selvage yarn transversely to the direction ofraising and lowering. The motion of the yarn guide structure required tocross the at least one selvage yarn is derived from the eccentric driveassociated with said selvage yarn.

The invention makes it possible to change the weave of selvage yarns andinserted fillings in a simple manner in the case of consecutive fillinginsertions because only the drive control need be changed. As regardsconsecutive insertions of fillings, the number of fillings interlacedwith the selvage yarns and/or the kind of mutual crossing of selvageyarns can easily be changed.

A selvage-forming device according to the invention offers the advantageof being highly compact and constituted of few parts. It can beimplemented in modular form. Moreover it can be installed anddisassembled in a simple manner and furthermore it can be shiftedwidth-wise of the power loom when the fabric width is changed.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages and features of the invention are elucidated below inthe description of illustrative embodiments and in relation to theattached drawings.

FIG. 1 is a schematic elevation of a selvage-forming device of theinvention as viewed in the direction of motion of the selvage yarns,

FIGS. 2-5 show the selvage-forming device of FIG. 1 in variouspositions,

FIG. 6 is a section along line VI--VI of FIG. 1, the distances betweenthe individual components in the direction of motion of the selvageyarns being exaggerated for clarity,

FIG. 7 shows a section along line VII--VII of FIG. 2,

FIG. 8 is an embodiment variation of a selvage-forming device in aposition corresponding to FIG. 5,

FIG. 9 is a section along Line IX--IX of FIG. 8,

FIGS. 10, 11 are weave patterns of selvage yarns and fillings madepossible by the selvage-forming device of FIGS. 1 through 6,

FIG. 12 shows on an enlarged scale an embodiment variation of thesegment F12 of FIG. 2,

FIG. 13 is a weave of selvage yarns and fillings implemented by theembodiment of FIG. 12,

FIG. 14 is an enlarged view similar to the segment F12 of FIG. 2 foranother embodiment variation,

FIG. 15 is a further embodiment of a selvage-forming device of theinvention,

FIG. 16 is a section along line XVI--XVI of FIG. 15,

FIGS. 17, 18 show the selvage-forming device of FIG. 15 in differentpositions,

FIG. 19 is an elevation of a further embodiment of a selvage-formingdevice,

FIG. 20 is an elevation of a selvage-forming device similar to that ofFIG. 19,

FIGS. 21, 22 show a further embodiment of a selvage-forming device ofthe invention in two different positions, and

FIGS. 23, 24 show a further embodiment of the invention of aselvage-forming device in two different positions.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

The selvage-forming device 1 shown in FIGS. 1 through 7 comprises twolateral guide segments 2 within which three yarn guide structures ordevices 3, 4 and 5 are guided in the longitudinal or vertical (up anddown) direction A. Two selvage yarns 8 and 11, each from a particularyarn supply, especially a bobbin, are consecutively raised and loweredin the longitudinal direction A in order to subtend consecutive selvagesheds 12 (FIG. 6). The yarn guide structures 3 and 4 each contain a slot6, 7. The slots 6, 7 of the consecutively mounted yarn guide structures3, 4 run in mutually opposite directions and obliquely to thelongitudinal direction A. The slots 6, 7 guide a selvage yarn 8. Whenthe yarn guide structures 3, 4 and hence the slots 6, 7 are movedmutually oppositely in the longitudinal direction A, the slots 6, 7 movethe selvage yarn 8 in the transverse direction B, that is transverselyto the longitudinal direction A. The yarn guide structure 5 contains aneedle 9 fitted at its end with a yarn eye 10 guiding a selvage yarn 11.The selvage yarns 8 and 11 are moved oppositely to each other in thelongitudinal direction A, that is they are being raised and lowered, inorder to form in each case a shed 12 which shall receive a filling.Thereupon a new shed is formed, that is, following the insertion of oneor more fillings, the selvage yarns 8, 11 together with the filling(s)will form a selvage weave. In the process the selvage yarns 8, 11 restaround the filling(s) in the manner furthermore shown in FIGS. 10, 11and 13. In addition to such looping, the invention also provides that atleast one of the selvage yarns 8 or 11 be alternatingly displaced in thetransverse direction so that they shall cross and loop each other, againas shown in FIGS. 10, 11 and 13.

The selvage-forming selvage device 1 contains an independentlycontrolled drive 13, for instance an electric drive motor controlledindependently of the loom drive by (not shown) means to make sheds fromwarps. By means of a drive shaft 14, the drive 13 actuates eccentricdrives moving the yarn guide structures 3, 4 for the selvage yarn 8 andthe selvage yarn 11 up and down in mutually opposite motions. Aneccentric drive comprises a crank 15 of which the end is connected to acoupling bracket 16 linked to the yarn guide structures 3, 4. In thisembodiment the eccentric drive comprises a Y-shaped crank bracket 16 andis connected at the connection points 19, 20 to the yarn guidestructures 3, 4 which are angularly configured relative to the axis ofrotation of the eccentric drive, that is relative to the drive shaft 14.The connection points 19, 20 thereby are located opposite each otherrelative to a plane of symmetry 21 extending through and including driveshaft 14. As a result, while the yarn guide structures 3, 4 are raisedand lowered simultaneously, each will however follow a somewhatdifferent path. Thereby the two yarn guide structures 3, 4 moverelatively to each other during the raising and lowering motions in thelongitudinal direction A, and consequently the slots 6, 7 also are movedrelatively to each other in the longitudinal direction A. The slots 6, 7are configured in such a way that parts of them always will overlap. Theoverlapping parts of the slots 6, 7 depend on the relative position ofthe yarn guide structures 3, 4 and hence of the slots 6, 7 in thelongitudinal direction A. For the position shown in FIG. 1, the centralparts of the slots 6, 7 will overlap, whereas at the largest relativedisplacements corresponding to the positions of FIGS. 2 and 4 the rightends or the left ends of the slots 6, 7 will overlap. Because theselvage yarn 8 always paper through the zone where the slots 6, 7 areoverlapping, the yarn will be correspondingly shifted in the transversedirection B relatively to the longitudinal direction A. To achieve thistransverse shifting, the radial length of the crank 15, the length ofthe coupling bracket 16, the position of the linkage points 19, 20 andthe length in the longitudinal direction A of the slots 6 and 7 are madeto match one another.

The drive shaft 14 drives the yarn guide structure 5 by means of a,another eccentric drive. This eccentric drive contains a crank 17mounted on the drive shaft 14 and in this embodiment is integral (onepiece) with the crank 15, the end of said crank 15 being linked at alinkage point 24 to a coupling rod of bar 18 of which the free end islinked by a linkage point 23 to the yarn guide structure 5. The linkagepoint 24 of the coupling bar 18 is essentially diametrically opposite inrelation to the drive shaft 14 to the linkage point 22 of the couplingbracket 16 and as a result, when the drive shaft 14 rotates the cranks15, 17, the yarn guide structures 3, 4 on one hand and the yarn guidestructure 5 on the other hand move with maximum excursion in oppositedirections.

The angle of rotation of the drive 13 is restricted to a range less than360°, that is to about 350°, as indicated by the positions of FIGS. 3and 5. For that purpose the crank 15 is fitted with a stop 29. The drive13, in particular a stepping motor, is controlled by a control unit 30that controls the direction of rotation, the path to be covered and alsothe speed.

The side guide segments 2 are part of a frame 31 also holding the drive13. The yarn guide structure 5 is in the shape of a yoke guided in twolongitudinal channels 36 of the side segments 2 and forming a linearguide for the yarn guide structure 5. The yarn guide structure 5comprises an eye 33 in the extension of the needle 9 to guide theselvage yarn 11. The yarn eye 10 is somewhat offset from the needle 9 inthe direction of motion of the selvage yarn 11 toward the fabric 32(FIG. 6), and as a result the selvage yarn 11 does not make contact inthe vicinity of the needle 9 and is easily threaded from the side of thefabric 32.

The two side segments 2 each comprise a longitudinal channel 34, 35constituting a linear guide for the yarn guide structures 3, 4 whichthereby are guided only unilaterally. Besides being connected by theY-shaped coupling bracket 16, the two yarn guide structures 3, 4 areconnected in their area away from the coupling bracket 16 by two linksbracket 25 linked at linkage sites 26, 27 to the yarn guide structures3, 4.

The embodiment of the invention of FIGS. 8 and 9 substantiallycorresponds to that of FIGS. 1 through 7 except that the Y-shapedcoupling bracket is replaced by a shorter T-shaped coupling bracket 16'linked by two further coupling rods or bars 42, 43 to the yarn guidestructures 3, 4. The coupling bar 42 linked at one linkage point 44 tothe coupling bracket 16' and at one linkage point 46 to the yarn guidestructure 3, and the coupling bar 43 linked at one linkage point 45 tothe coupling bracket 16' and at one linkage point 47 to the yarn guidestructure 4, make possible compensation whereby the yarn guidestructures 3, 4 can be guided by T-shaped ends 37, 38 in undercutchannels 34, 35 of the side segments 2. The same effect also can beachieved if, in an embodiment not shown, the Y-shaped coupling bracket16 of the embodiment of FIGS. 1 through 7 is replaced by two separatecoupling bars of which one connects the linkage point 22 of the crank 15to the linkage point 19 of the yarn guide structure 3 and the otherconnects the linkage point 22 of the crank 15 to the linkage point 20 ofthe yarn guide structure 4. In this embodiment, the crank 17 is combinedwith a stop 48.

When using a Y-shaped coupling bracket 16 corresponding to theembodiment of FIGS. 1 through 7, the distance between the linkage points19, 20 as seen in the transverse direction B will change during themotion of the corresponding eccentric drive. This change in distance canbe absorbed by the play in the guide channels 34, 35 and/or by elasticdeformation of the coupling bracket 16 and/or by elastic deformation ofthe brackets 25. Moreover the guide channels 34, 35 may also be made toslightly curve relative to each other in an upper and lower zone tocompensate thereby the change in distance between the linkage points 19,20.

An open shed 12 is present in the embodiment of FIGS. 1 through 7 (andcorrespondingly also in the embodiment of FIGS. 8 and 9), namely in thepositions of FIG. 1, FIG. 3 and FIG. 5, whereby a filling 49 can beinserted in each of these three positions. Upon presetting the controlunit 30, a predetermined pattern may be used selectively in each ofthese positions, said patterns being easily modified at the control unit30. If for instance the positions of FIG. 1, FIG. 3 and FIG. 5 areconsecutively used to insert fillings (FIG. 10), and a filling 49 isinserted in each of these positions, the weave pattern shown in FIG. 10will result, wherein the selvage yarn 8 is to the side of the selvageyarn 11 only at every second filling insertion. If on the other hand thepositions of FIGS. 3 and FIG. 5 are consecutively used for fillinginsertion, a weave pattern as shown in FIG. 11 will result, wherein theselvage yarn 8 is to the side of the selvage yarn 11 at every fillinginsertion. Starting with the position of FIG. 1, the position of FIG. 2or the position of FIG. 4 can be selectively used by appropriatelyrotating the drive shaft 14 so that the selvage yarn 8 is shiftedselectively to the right or left of the selvage yarn 11.

Moreover, the fillings may be inserted only in the positions of FIG. 1and FIG. 3 for instance in the case of a predetermined number of fillinginsertions and thereupon the procedure may be changed to fillinginsertions in the position of FIG. 1 and FIG. 5. All these proceduresare easily selected by adjusting the control unit 30.

As shown in FIG. 12, the embodiment of FIGS. 1-7 or FIGS. 8 and 9 can bemodified in simple manner in that the yarn guide structures 3, 4 arefitted with two pairs of slits 6,7 and 40, 41 configured one behind theother in the longitudinal direction A and each receiving one selvageyarn 8, 39. The slots 6, 40 and 7, 41 of the yarn guide structures 3, 4are mutually opposite and oblique so that the selvage yarns 8, 39 areshifted in each instance in mutually opposite manner in the transversedirection B relative to the selvage yarn 11. If in this instance thepositions of FIG. 3 and FIG. 5 are used for filling insertion, a weavepattern corresponding to FIG. 13 may be made.

As shown in FIG. 14, the embodiment of FIGS. 1-7 or of FIGS. 8 and 9 canbe easily modified by fitting the yarn guide structures 3, 4 withseveral pairs of slots 6, 7 mounted adjacent to each other in thetransverse direction and each receiving one selvage yarn 8. A needle 9with eye 10 to guide selvage yarns 11 is associated to each of saidpairs of slots. As further shown in FIG. 14, it is easily possible notonly to configure several pairs of slots 6, 7, adjacent to each other inthe transverse direction B, in the yarn guide structures 3, 4, but alsoseveral pairs of slots 6, 7 and 40, 41 below each other in thelongitudinal direction A and each receiving a selvage yarn 8, 39.

Again yarn guide structures for the selvage yarns are raised and loweredby cam drives in the embodiments of selvage-forming devices 1 of theinvention shown in FIGS. 15 through 24, and furthermore the motion bywhich at least one selvage yarn shall be shifted transversely in orderto transversely cross the other selvage yarn may also be derived from aneccentric drive.

In the embodiment of FIGS. 15 through 18, the coupling bar 16a of one ofthe eccentric drives and driven by the crank 15 is fitted with a yarnguide element in the form of an eye 50, whereby this coupling bar 16aper se is designed to be a yarn guide structure. The coupling bar 16adesigned as a yarn guide structure is guided inside a guide bush 52acting as a linear guide means for the coupling bar 16a. The guide bush52 is rotatable about a shaft 53 mounted in stationary manner to theframe 31. The end of the coupling bar 16a projecting from the guide bush52 and fitted with the eye 50 can be displaced over a substantialexcursion in the direction B transversely to the longitudinal directionA. The selvage yarn 8 guided by the eye 50 moves transversely to thesecond selvage yarn 11 during the raising and lowering procedure and isguided by an eye 10 in a needle 9 projecting from a yoke-shaped yarnguide structure 5a. The yarn guide structure 5a is guided inside linearguide means (longitudinal channels) of the side segments 2 of a frame31. A coupling bar 18 of a second eccentric drive acts on said yarnguide structure 5a and is linked to a crank 17 driven by the drive shaft14.

A shed 12 for receiving filling insertion is formed in the positionshown in FIG. 18. Based on this position, the drive 13 can be controlledin such manner that the position of FIG. 15 or the position of FIG. 17can be selected. The selvage yarn 8 running through the eye 50 of thecoupling bar 16a thereby can be selectively shifted to the right or leftof the needle 9. In this manner various weaves can be implemented.

As shown in FIG. 16, the drive shaft 14 of the drive 13 of thisembodiment is combined with a position sensor 59 outputting a positionsignal and connected to the control unit 30. This position sensor 59,for instance an incremental generator, allows using illustratively aservomotor as a drive 13 and thereby to accurately move the servomotionto the desired position. It is thereby possible to omit the stop forlimiting the angle of rotation. If such a position sensor 59 iscooperating with a stepping motor, then obviously a stop otherwiserequired for adjustment can be eliminated.

In the embodiment shown in FIG. 19, the yarn guide structure 5acorresponds to the yarn guide structure of the embodiment of FIGS. 15through 18. The coupling bar 16b driven by the crank 15 is designed as ayarn guide structure and is fitted with two eyes 50, 51. The couplingrod or bar 16b is linked to a yoke-shaped component 63 guided in thelongitudinal direction A in linear guides of the side segments 2 of theframe 31. The coupling bar 16b is connected by a linkage point 54 to thecomponent 63. The eye 50 is located underneath the linkage point 54 andthe eye 51 above it, whereby these two eyes move in mutually oppositedirections relative to said linkage point and to the needle 9 when theeccentric drive pivots the coupling bar 16b.

The illustrative embodiment of FIG. 20 differs from that of FIG. 19 inthat a yarn guide structure 55, 56 is mounted by means of pins 57, 58resp. to the coupling bar 16b above and below the linkage point 54whereby the coupling bar 16b is connected to the yoke-shaped component63, said yarn guide structure being guided in the transverse directionB. These yarn guide structures are fitted with eyes 50a, 51a configuredon each side of the coupling bar 16b. The yarn guide structure 5b isfitted with two needles 9 and eyes 10 for two selvage yarns 11, the eyes50a, 51a of the yarn guide structures 55, 56 being shiftable in relationto the direction of rotation of the drive shaft 14 to the right or leftside relative to said selvage yarns 11.

In principle, the embodiment of FIGS. 21 and 22 corresponds to that ofFIG. 19. The difference lies in the coupling bar 16b being rotatablysupported about a shaft 61 by means of a block 60 in a yoke-shapedcomponent 63a. The yoke-shaped component 63a is guided in the sidesegments 2 of the frame 31 in the longitudinal direction A inside linearguides, for instance channels. The coupling bar 16b is held in the block60 by securing clamps 62.

Basically the embodiment of FIGS. 23 and 24 corresponds in its design tothat of FIGS. 21 and 22, however the coupling bar 16c is designed as ayarn guide and fitted with an eye 50 at its end and is divided into twoparts 64, 65. The part 64 is linked by a linkage point 22 to the crank15 and by a linkage point 66 to a yoke-shaped component 63b guided inthe longitudinal direction A in linear guides of the side segments 2 ofthe frame 31. The part 65 is linked a distance away from the linkagepoint 66 by a linkage point 67 also to the yoke-shaped component 63b.The parts 64 and 65 are connected between the two linkage points 66 and67 by a hinge joint 68 allowing axial compensation, and thereby the part64 of the coupling bar 16c drives the part 65 into pivoting motioncorresponding to the pivoting motion of its own. By dividing thecoupling bar 16c into two parts 64, 65 connected to each other inmutually articulating manner, the motion of the eye 50 in the directionB transverse to the longitudinal direction A can be prescribedindependently of the amplitude of the pivoting motion of the part 64 ofthe coupling bar 16c. Depending on the selected positions of the linkagepoints 66 and 67 and on the position of the hinge joint 68 and thelength of the part 65, it is possible to select the transversedisplacement of the eye 50 over a given excursion.

All the above discussed embodiments of selvage-forming devices 1 allowdifferent interlacings, i.e. weaves of fillings with selvage yarns 8,39, 11, the desired weave being attained by controlling the drive 13 bythe control 30 according to a selectable pattern. The selected patternillustratively is such that the position of the drive shaft 14 of theselvage-forming device 1 is determined by the loom's main shaft positionand accordingly the position of this drive shaft 14 is synchronous withthe motions of the other loom components. Selvage yarns 8, 39, 11 withpredetermined weaves can be implemented in arbitrary sequences bycontrolling the drive element 13 in an appropriately selected manner.

Even though the cranks 15, 17 of the eccentric drives are of differentlengths in the above embodiments, they obviously also may be ofidentical length. Correspondingly, the coupling bars/brackets 16 and 18of the eccentric drives may be of different or equal lengths. The lengthof the components is selected in such manner that the shed 12 formed bythe selvage yarns 8, 39 and 11 approximately coincides with that shedwhich is formed by the loom's shed-forming means with omitted warps. Forthat purpose the selvage-forming device 1 may be mounted by its frame 31at a suitable loom position. Preferably the component length is selectedin such a way that the raised and lowered selvage yarns 8, 39 and 11will cross in the transverse direction when the pivoting motion of thecoupling bracket/bar 16 is at approximately its maximum value.Illustratively the drive element 13 consists of a stepping motor forwhich the position, speed and acceleration are predetermined by thecontrol unit 30. The stop 29 or 48 is used in this respect to adjust theposition of the drive element 13 in known manner using a controlprogram.

Moreover the drive element 13 may consist also of a controlledservomotor. In this case a position sensor 59 as shown in FIG. 16 isrequired. This position sensor 59 detects the angular position of thedrive shaft 14 and feeds it to the control unit 30. If a position sensor59 is used jointly with a stepping motor, stops obviously no longer areneeded. The drive element 13 also may be a hydraulic or pneumatic drivemotor. In this design, valves appropriately controlled by the controlunit 30 are required.

If the selvage-forming device 1 is mounted inside a frame 31 affixed atan arbitrary location of the loom, then the selvage-forming unit shallbe a module connected only by fasteners and electric, pneumatic orhydraulic feeds to the loom.

The selvage-forming device need not mandatorily contain its own controlunit 30 because the function of the unit 30 also may be integrated intothe loom's control system.

As shown in FIG. 6, a manually operated switch 28 may be associated withthe control unit 30 to allow an operator to control the drive element 13so that the drive shaft 14 assumes a specific angular position whereatthe yarn guide structures are easily accessible and can be well caredfor.

In the above embodiments, the yarn guiding eyes 10, 50 and 51, 50a, 51aare shown circular. Obviously they also may assume other shapes, forinstance oval or slotted.

All the above embodiments provide that one of the selvage yarns 11 or aset of selvage yarns 11 be raised and lowered in one plane only.Obviously the selvage forming device may be modified in such manner thatall selvage yarns shall be displaced relative to each other also in thetransverse direction B during the raising and lowering motions used informing a shed 12. In such a case, eccentric drives must be provided toallow transverse displacement for all selvage yarns raised and loweredin mutually opposite directions.

In the embodiments shown above, the angular range of the drive element13 is limited, whereby the drive element is alternatingly actuated inboth directions of rotation. However the coupling brackets/bars 16 and18 may also be driven by a crankshaft whereby the drive element 13 needbe driven unidirectionally only or illustratively as regards theconsecutive insertion of several fillings in one direction of rotation,the direction of rotation then being reversed.

The selvage forming devices of the above embodiments may be used withany kind of loom, that is with jet looms, gripper looms, projectilelooms and others.

The invention is not restricted to the above shown and discussedembodiments. Instead many modifications, also combinations of theparticular embodiments, may be resorted to. Protection is solely definedby the claims.

We claim:
 1. In a selvage forming device for a power loom having a maindrive system wherein the selvage forming device includes yarn guidestructures movably guided for mutually opposing motions to raise andlower at least two selvage yarns to sequentially form selvage sheds andto periodically cause at least one selvage yarn to periodically cross atleast one other selvage yarn in a direction transversely of the raisingand lowering direction, the improvement comprising:a selvage drivemotor; a selvage drive arrangement connected to the yarn guidestructures and when actuated driving the structures to periodicallyraise and lower them with mutually opposing motions and, during suchraising and lowering, causing at least one selvage yarn to periodicallycross at least one other selvage yarn in a direction transversely of theraising and lowering direction; said drive arrangement includingeccentric drives connected between said selvage drive motor and the yarnguide structures; said selvage drive motor being independentlycontrollable to vary the motion of the eccentric drives and the yarnguide structures.
 2. The improvement as claimed in claim 1, said drivearrangement including a pivot shaft driven in rotation by the selvagedrive motor and drivingly connected to said eccentric drives for movingthe yarn guide structures, said shaft extending parallel to theprincipal direction of selvage yarns approaching the selvage shed;thedriving connection between the eccentric drives and the respective yarnguide structures that cause said at least one selvage yarn toperiodically cross said at least one other selvage yarn comprising asingle coupling bracket/bar (16, 16', 16a, 16b, 16c) connected to bothsaid last-recited yarn guide structures.
 3. The improvement as claimedin claim 1, including a rotatable pivot shaft driven in rotation by saidselvage drive motor and drivingly connected to said eccentric drives formoving the yarn guide structures, and wherein a pair of said eccentricdrives is driven by said pivot shaft via connections located ondiametrically opposed sides of said pivot shaft.
 4. The improvement asclaimed in claim 1, said eccentric drives connected to said selvagedrive motor for alternating rotary motion within a range not greaterthan about 360° of rotation.
 5. The improvement as claimed in claim 4,including a stop device located adjacent said selvage drive arrangementand positioned so as to positively limit rotation of said eccentricdrives.
 6. The improvement as claimed in claim 4, including a positionsensor associated with the selvage drive arrangement and arranged togenerate position signals indicative of the position of the eccentricdrives; and a controller for said selvage drive motor arranged toreceive said position signals and to control said drive motor inresponse to said signals.
 7. The improvement as claimed in claim 1,wherein said selvage drive motor is a stepping motor.
 8. The improvementas claimed in claim 1, wherein a pair of said yarn guide structures arearranged to cause said at least one selvage yarn to cross at least oneother selvage yarn, said pair of yarn guide structures mounted adjacenteach other in the direction of yarn motion and including mutuallycrossing slots (6, 7) together configured for guiding a selvage yarn tobe displaced transversely of the raising and lowering directions of theyarn guide structures, to thereby cause the crossing of at least oneselvage yarn relative to the other.
 9. The improvement as claimed inclaim 8, said drive arrangement including a pivot shaft driven inrotation by the selvage drive motor and drivingly connected to saideccentric drives for moving the yarn guide structures; and wherein saidpair of selvage yarn guide structures are connected to a common one ofsaid eccentric drives via at least one coupling bracket, the connectionpoints between said at least one coupling bracket and the respectiveselvage guide structures being arcuately spaced apart relative to theaxis of rotation of said pivot shaft.
 10. The improvement as claimed inclaim 9, wherein the shape of said coupling brackets is selected fromthe group consisting of Y and T.
 11. The improvement as claimed in claim8, wherein said at least one pair of yarn guide structures is mounted intransversely opposed linear guides.
 12. The improvement as claimed inclaim 8, wherein each one of said at least one pair of yarn guidestructures has opposed end areas and is connected at one end area to aneccentric drive, and including a bracket link pivotally connected to andextending between the other end areas of said yarn guide structures. 13.The improvement as claimed in claim 1, wherein one of said eccentricdrives includes a coupling bar (16a, 16b, 16c) that comprises a portionof one of said yarn guide structures.
 14. The improvement as claimed inclaim 13, including a rotatable pivot shaft drivingly connected to saidselvage drive motor and drivingly connected to said eccentric drives formoving said yarn guide structures, and wherein said coupling bar havingopposed end areas, is pivotally mounted by a pivot having a pivot axisextending parallel to said pivot shaft to a yoke component guided for upand down motion between said end areas, is connected to a part of one ofsaid eccentric drives at one of said end areas, and has a selvage yarnguide element at the other opposed end area, said one of said eccentricdrives arranged so as to cause said connecting bar and yoke component toreciprocate up and down and to pivot about said pivot in response tomotion of said one of said eccentric drives.
 15. The improvement asclaimed in claim 14, wherein said movable yoke component (63) is guidedfor up and down linear motion.
 16. The improvement as claimed in claim15, including yarn guide elements (55, 56) carried by to said connectingbar (16b) at points spaced away from said pivot, with at least one yarnguide element located on each side of said pivot along the length of theconnecting bar.
 17. The improvement as claimed in claim 13, wherein saidcoupling bar (16c) is formed of a pair of coupling bar portions (64,65), one of said portions connected to a portion of one of saideccentric drives at one end area thereof and connected by an articulatedconnection to the other of said coupling bar portions at an opposed endarea thereof; said connecting bar portions each pivotally connected by arespective pivot to a yoke component between opposed ends of saidconnecting portions, said articulated connection located between saidpivots, the other of said coupling bar portions including a selvage yarnguide element (50) at an end thereof opposite the end area articulatedwith the one coupling bar portion.
 18. The improvement as claimed inclaim 1, wherein one of said yarn guide structures (5, 5a, 5b) includesat least one yarn guide element (10) at one end area thereof and isconnected to one of said eccentric drives at an opposed end areathereof; and including a linear guide element, said one yarn guidestructure guided for linear up and down motion in said linear guidestructure.
 19. The improvement as claimed in claim 18, said one of saidyarn guide structures comprising a needle portion extending in adirection parallel to the raising and lowering motion of said yarn guidestructure, said yarn guide element located at an end area of said needleportion.
 20. The improvement as claimed in claim 19, wherein said one ofsaid yarn guide structures includes at least one selvage yarn eyeletconfigured to guide a selvage yarn from one side to the opposite side ofa portion of said one of said guide structures, said eyelet located at adistance from said selvage yarn guide element between one of saideccentric drives and said selvage yarn guide element.
 21. Theimprovement as claimed in claim 1, said selvage forming device includinga frame, and wherein said yarn guide structures and eccentric drives aremounted on said frame.
 22. The improvement as claimed in claim 1, saidselvage drive arrangement including coupling bracket/bar members havingbracket/bar lengths connecting each eccentric drive to a respective yarnguide structure, said coupling bracket/bar members driven by arespective eccentric drive so that they have a maximum pivotalexcursion, said selvage drive arrangement including a pivot shaftperiodically driven in rotation by the drive motor, and cranks havingcrank lengths connecting said coupling bracket/bar members to the pivotshaft, said coupling bracket/bar lengths and configurations and saidcrank lengths and configurations being selected so that the crossing ofthe selvage yarns will occur at approximately the maximum periodicexcursion of the coupling bracket/bar members.